A method for preparing a basalt fiber separator, a product and an application thereof

Abstract

This invention relates to the field of inorganic fiber materials and electrochemical energy storage technology, and particularly to a method for preparing a basalt fiber membrane, its product, and its application. The method for preparing the basalt fiber membrane includes the following steps: adding basalt fibers to a solution of substance A and ultrasonically treating them, followed by mechanical shearing and filtration to obtain loosened basalt fibers; combining the loosened basalt fibers with an adhesive, followed by hot pressing to obtain the basalt fiber membrane; substance A in the solution is a mixture of sodium polyacrylate and polyvinylpyrrolidone, or a copolymer of acrylic acid and vinylpyrrolidone. The basalt fiber membrane prepared using this method has high porosity (>75%), exhibits significant effect in suppressing zinc dendrites in symmetrical zinc-ion batteries, and achieves a battery cycle life exceeding 1200 hours.

Description

Technical Field

[0001] This invention relates to the field of inorganic fiber materials and electrochemical energy storage technology, and in particular to a method for preparing basalt fiber membranes, products and applications. Background Technology

[0002] Zinc-ion batteries have attracted much attention due to their high safety and low cost, but their cycle life is limited by zinc dendrite growth and electrolyte corrosion. Traditional separators (such as glass fiber and polypropylene membranes) have problems such as low porosity, poor electrolyte wettability, insufficient alkali resistance, poor mechanical strength, and poor battery cycle performance.

[0003] Basalt fiber possesses high strength, high temperature resistance, and corrosion resistance; however, untreated fibers are prone to agglomeration, leading to uneven film formation and affecting ion transport efficiency. Commonly used mechanical dispersion methods easily damage the fiber structure, chemical treatment generates a large amount of acidic waste liquid, and plasma treatment is costly. Furthermore, existing research on the application of basalt fiber membranes in batteries is limited, and there is a lack of optimized designs specifically for the needs of zinc-ion batteries. Summary of the Invention

[0004] Based on the above, the present invention provides a method for preparing basalt fiber membranes, products, and applications.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of this invention is a method for preparing a basalt fiber membrane, comprising the following steps:

[0007] Basalt fibers were added to solution A and ultrasonically treated, followed by mechanical shearing and filtration to obtain disintegrated basalt fibers.

[0008] The sparsed basalt fibers are combined with an adhesive and then hot-pressed to obtain a basalt fiber membrane.

[0009] Substance A in the solution is a mixture of sodium polyacrylate and polyvinylpyrrolidone, or a copolymer of acrylic acid and vinylpyrrolidone.

[0010] The second technical solution of the present invention is a basalt fiber membrane prepared according to the above preparation method; the basalt fiber membrane has a porosity of 70-85% and a thickness of 20μm-2mm.

[0011] The third technical solution of the present invention is a zinc-ion battery, comprising electrode material, separator and electrolyte;

[0012] The diaphragm is made of the aforementioned basalt fiber diaphragm.

[0013] The present invention discloses the following technical effects:

[0014] This invention achieves efficient fiber dispersion while avoiding damage through a synergistic process of "Substance A + ultrasonic treatment + mechanical shearing". Substance A adsorbed on the fiber membrane surface enhances compatibility with the electrolyte and reduces interfacial impedance. The preparation method of this invention avoids the generation of acidic wastewater, and the waste liquid after filtration can be reused after replenishing with Substance A.

[0015] The basalt fiber membrane prepared by the method of this invention has a high porosity (>75%), which is very effective in suppressing zinc dendrites in symmetrical zinc-ion batteries, and the battery cycle life exceeds 1200 hours.

[0016] The basalt fiber membrane of the present invention is suitable for electrolyte environments with different pH levels and has better corrosion resistance than traditional glass fiber membranes. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 Photograph of the detached basalt fibers prepared in Example 1.

[0019] Figure 2 Photograph of the detached basalt fibers prepared in Example 2.

[0020] Figure 3 Photograph of the basalt fiber dispersion prepared in Example 3 after standing for 2 hours.

[0021] Figure 4 Photograph of the detached basalt fiber membrane prepared in Example 3.

[0022] Figure 5 Photograph of the basalt fiber diaphragm prepared in Example 3.

[0023] Figure 6 Scanning electron microscope image of the basalt fiber membrane prepared in Example 3.

[0024] Figure 7 To achieve a 1 mA / cm² speed for the zinc-ion battery using the basalt fiber membrane described in Example 3. 2 @1mAh / cm 2 The cyclic curve.

[0025] Figure 8 Photograph of the detached basalt fiber membrane prepared in Example 4. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0031] This invention provides a high-efficiency, low-cost process for the decomposition and film formation of basalt fibers, producing fiber membranes with high porosity, uniform structure, and strong corrosion resistance, which can be used to improve the cycle stability and safety of zinc-ion batteries. Details are as follows:

[0032] The first aspect of this invention provides a method for preparing a basalt fiber membrane, comprising the following steps:

[0033] Basalt fibers were added to solution A and ultrasonically treated, followed by mechanical shearing and filtration to obtain disintegrated basalt fibers.

[0034] The sparsed basalt fibers are combined with an adhesive and then hot-pressed to obtain a basalt fiber membrane.

[0035] Substance A in the solution is a mixture of sodium polyacrylate and polyvinylpyrrolidone, or a copolymer of acrylic acid and vinylpyrrolidone.

[0036] In this invention, substance A plays a role in altering the surface charge and zeta potential of basalt fibers, thereby promoting the disintegration and stable dispersion of basalt fibers.

[0037] In a preferred embodiment of the present invention, substance A is a mixture or copolymer of sodium polyacrylate and polyvinylpyrrolidone in a mass ratio of (0.1 to 10):1, and the mass concentration of the solution of substance A is 0.2% to 3%.

[0038] In a preferred embodiment of the present invention, the length of the basalt fiber is 6-28 mm; the mass-to-volume ratio of the basalt fiber to the substance A solution is (0.1-1) g: 100 mL.

[0039] In a preferred embodiment of the present invention, the power of the ultrasonic treatment is 100-1000W and the time is 3-6h.

[0040] In a preferred embodiment of the present invention, the mechanical shearing method is magnetic stirring, mechanical stirring, or treatment with a disintegrating machine for 4-8 hours.

[0041] The present invention does not impose any particular limitation on the vacuum degree of the filtration, and adopts a filtration vacuum degree known to those skilled in the art, such as 10-100 Pa.

[0042] In a preferred embodiment of the present invention, the adhesive is at least one selected from polyvinyl alcohol, carboxymethyl cellulose, polyacrylate, ethylene-vinyl acetate copolymer, acrylonitrile copolymer and polyvinyl acetate resin;

[0043] The method of combining the detached basalt fibers with the adhesive is as follows: the adhesive is directly added to the solution of substance A (method 1), or the adhesive is prepared into a solution or suspension with a mass concentration of 1% and then permeated through the filtration membrane formed by the detached basalt fibers (method 2).

[0044] When using method two, the mass-to-volume ratio of basalt fiber to adhesive solution is 0.5g:50mL.

[0045] In a preferred embodiment of the present invention, the hot pressing pressure is 2-15 MPa, the temperature is 100-300°C, and the time is 2 hours.

[0046] A second aspect of the present invention provides a basalt fiber membrane prepared according to the above-described preparation method; the basalt fiber membrane has a porosity of 70-85% and a thickness of 20 μm-2 mm.

[0047] A third aspect of the present invention provides a zinc-ion battery, comprising an electrode material, a separator, and an electrolyte;

[0048] The diaphragm is made of the aforementioned basalt fiber diaphragm.

[0049] In a preferred embodiment of the present invention, the electrode material is a zinc electrode; and the electrolyte is an aqueous solution of zinc sulfate.

[0050] The basalt fiber separator of this invention adsorbs hydrophilic groups on its surface, significantly improving electrolyte wettability. When used as a separator in a zinc-ion battery, its uniform porous structure inhibits zinc dendrite growth, reduces interfacial impedance, and enables the assembled symmetrical zinc battery to achieve a performance of 5 mA / cm². 2 The membrane exhibits stable cycling performance exceeding 1200 hours, representing a 240% improvement in cycle life compared to traditional glass fiber membranes. This invention boasts low-cost, environmentally friendly, and highly efficient processes, producing a fiber membrane with both high strength and corrosion resistance, making it suitable for high-safety, long-life zinc-ion battery systems.

[0051] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0052] The main components of the basalt fiber used in this embodiment of the invention are as follows: silicon dioxide content is 45-60%, aluminum oxide content is 12-19%, calcium oxide content is 6-12%, and iron oxide content is 5-15%.

[0053] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] Dissolve 1g of sodium polyacrylate in 100mL of deionized water, add 0.5g of basalt fiber with a length of 6mm, sonicate at 100W for 4h, then magnetically stir for 6h, and directly filter to obtain the sparsed basalt fiber.

[0056] The photograph of the detached basalt fibers prepared in this embodiment is shown below. Figure 1 As shown: by Figure 1 It can be seen that the disintegrated basalt fibers are independent of each other, short in size, only 6mm in length as the raw material, and cannot form a self-supporting membrane.

[0057] Example 2

[0058] The only difference from Example 1 is that 0.5g of polyvinylpyrrolidone was used instead of an equal mass of sodium polyacrylate.

[0059] The photograph of the detached basalt fibers prepared in this embodiment is shown below. Figure 2 As shown: by Figure 2 It can be seen that the loosened basalt fibers are mutually attracted and entangled, forming fibers longer than the original 6mm length of the raw material. (Comparison) Figure 1 and Figure 2 It can be seen that the addition of polyvinylpyrrolidone is beneficial for obtaining longer self-assembled basalt fibers, but it still cannot form a self-supporting membrane.

[0060] Example 3

[0061] Dissolve 0.5g sodium polyacrylate and 0.5g polyvinylpyrrolidone in 100mL of deionized water, add 0.5g basalt fiber with a length of 18mm, sonicate at 100W for 4h, then mechanically stir for 6h. The resulting disintegrated basalt fiber dispersion showed no significant sedimentation after standing for more than 2 hours. Figure 3 Direct filtration yields a loosened basalt fiber membrane. 50 mL of a 1 wt% polyvinyl alcohol solution (water as solvent) is filtered through the basalt fiber membrane, and the membrane is then hot-pressed at 100°C for 2 hours to obtain a basalt fiber diaphragm.

[0062] The photograph of the detached basalt fiber membrane prepared in this embodiment is shown below. Figure 4 As shown: by Figure 4 It can be seen that basalt fibers with an inherent length of 18 mm can be decomposed to obtain fibers with a length greater than 18 mm, and can form a self-supporting membrane, but it is relatively loose and the bonding force between fibers is insufficient.

[0063] A photograph of the basalt fiber membrane prepared in this embodiment is shown below. Figure 5 As shown: by Figure 5 It can be seen that, after being bonded by the adhesive, the basalt fiber membrane is no longer loose, and the bonds between the fibers become very tight; its microstructure is as follows. Figure 6 As shown, although there is a small amount of adhesive film between the fibers of the basalt fiber membrane, the pores between the fibers are well developed, and the individual fibers are clearly visible and the structure is complete.

[0064] The basalt fiber membrane prepared in this embodiment is sandwiched with two zinc electrodes to form a symmetrical zinc-ion battery, such as... Figure 7 As shown, a battery using a 2 mol / L zinc sulfate aqueous solution as the electrolyte can be stably cycled for more than 1200 hours. However, a battery assembled with a traditional glass fiber diaphragm (purchased from Whatman, GF / D thickness 675 μm) as the diaphragm failed due to a soft short circuit after 100 hours of the same test.

[0065] Example 4

[0066] Weigh 0.5g of acrylic acid monomer and 0.5g of vinylpyrrolidone and dissolve them in 10mL of deionized water. Then add 0.01g of ammonium persulfate as an initiator and react at 70℃ for 6h. After that, add 90mL of deionized water to dilute and obtain an aqueous solution of acrylic acid and vinylpyrrolidone copolymer with a concentration of 1wt%. Then add 0.5g of basalt fiber with a length of 18mm and sonicate at 100W for 4h. Then stir mechanically for 6h and filter directly to obtain a disintegrated basalt fiber membrane (that is, the only difference from Example 3 is that 1g of acrylic acid and vinylpyrrolidone copolymer is used instead of 0.5g of sodium polyacrylate and 0.5g of polyvinylpyrrolidone).

[0067] The photograph of the detached basalt fiber membrane prepared in this embodiment is shown below. Figure 8 As shown: by Figure 8 It can be seen that the basalt fiber membrane prepared in this embodiment is similar to that in Example 3. Figure 4 similar.

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A zinc-ion battery, characterized in that, This includes electrode materials, diaphragms, and electrolytes; The diaphragm is made of basalt fiber. The method for preparing the basalt fiber membrane is characterized by comprising the following steps: Basalt fibers were added to solution A and ultrasonically treated, followed by mechanical shearing and filtration to obtain disintegrated basalt fibers. The sparsed basalt fibers are combined with an adhesive and then hot-pressed to obtain a basalt fiber membrane. Substance A in the solution is a mixture of sodium polyacrylate and polyvinylpyrrolidone, or a copolymer of acrylic acid and vinylpyrrolidone; Substance A is a mixture or copolymer of sodium polyacrylate and polyvinylpyrrolidone in a mass ratio of (0.1~10):1, and the mass concentration of the solution of substance A is 0.2%~3%. The length of the basalt fiber is 6-28 mm; The ultrasonic treatment has a power of 100-1000 W and a duration of 3-6 h; The mechanical shearing method is magnetic stirring, mechanical stirring, or treatment with a disintegrating machine for 4-8 hours.

2. The zinc-ion battery according to claim 1, characterized in that, The mass-to-volume ratio of the basalt fiber to the solution of substance A is (0.1~1) g: 100 mL.

3. The zinc-ion battery according to claim 1, characterized in that, The adhesive is at least one of polyvinyl alcohol, carboxymethyl cellulose, polyacrylate, ethylene-vinyl acetate copolymer, acrylonitrile copolymer and polyvinyl acetate resin; The method of combining the detached basalt fibers with the adhesive is as follows: the adhesive is directly added to the solution of substance A, or the adhesive is prepared into a solution or suspension with a mass concentration of 1% and then permeated through the filtration membrane formed by the detached basalt fibers.

4. The zinc-ion battery according to claim 1, characterized in that, The hot pressing is performed at a pressure of 2-15 MPa, a temperature of 100-300℃, and a time of 2 hours.

5. The zinc-ion battery according to claim 1, characterized in that, The electrode material is a zinc electrode; the electrolyte is an aqueous solution of zinc sulfate.

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